Question

Bobby's cat runs x mph. Bobby's dog runs twice as fast as his cat.

Answer 1

Answer;

They will be 0.5x miles away from each other

Explanation;

Since the dog runs twice the speed of the cat

Its speed will be 2 * x = 2x mph

Now we want to know how far they will be from each other after 30 minutes

Kindly note that 30 minutes is 1/2 hour

Mathematically;

distance = speed * time

Distance of cat = x * 1/2 = 0.5x miles

Distance of dog = 2x * 0.5 = x miles

The dog is x - 0.5x miles = 0.5x miles away from the cat